1. Field of the Invention
The present invention concerns a sorting table with sorter rolls for the elimination of foreign matter remaining mixed in with the products of the harvest of small fruit. It applies as well to harvesting machines, and in particular to grape-picking machines equipped with one or several sorting tables with sorter rolls.
According to a particularly interesting application, the sorting table with sorter rolls according to the invention is intended to ensure the elimination of foreign matter (leaf stalks, leaves, pieces of leaves or tendrils, splinters of posts or stakes, mineral debris, insects, small animals, etc. . . . ) remaining mixed in with grapes, after the de-stalking of the crop.
However, this advantageous application is not limited to a sorting table for grapes. According to the invention, the sorting table may also be used for extracting foreign matter from the products of the harvest of various small fruits, such as red currants, black currants, blackberries, raspberries, bilberries, cranberries, olives, etc.
Considering the particularly interesting application envisaged for the processing of grapes, the invention is nevertheless described hereafter in relation to this application.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
With the majority of applications of wine-making methods, grapes are first de-stalked prior to masking and/or pressing of the grapes. This de-stalking operation, which is performed by different methods and mechanical devices, is meant to detach the berries from the bunch of grapes and to separate said berries from the stalks to which they are still attached after the harvest and to avoid the presence of bitterness and herbal and vegetable tastes in the wine.
However, after this de-stalking operation, whether this may or may not have been preceded by a cleaning operation of the crop, a certain percentage of debris and foreign matter remains mixed in with the grapes, so that a sorting operation is necessary to extract these, if one does not want the presence of such foreign matter to alter the qualities of the wine and in particular its organoleptic qualities.
This sorting operation can be performed manually or automatically on a sorting table that has been set up for one of the other of these sorting modes.
Linear sorting tables intended for manual sorting feature a support on which the crop is spread out and persons charged with the sorting task are positioned on either side of it. This support may be static in its most rustic form, but it is most often provided either with some movement so the crop that is spread out in a thin layer can travel past these persons for sorting, or it consists of an inclined vibrating tray. The conveyor belt or vibrating tray may be equipped with perforations to allow the layer of grapes being cleaned and moving towards the crop receiving container. This sorting method requires the search for and the availability of seasonal labor, and it requires them to pay close attention to the task, its productivity being very mediocre. Also, the results tend to be quite uneven. Of course, such sorting tables cannot be placed on grape-picking machines.
Automatic vibrating tables feature a table formed by a perforated tray which is subjected to vibrations allowing a spreading and movement of the grapes. The berries pass across the tray perforations during their travel and are recovered under said vibrating, for example in a grape pump. The pieces of vegetable debris which are larger than the perforations advance under the effect of the vibrations and are evacuated by gravity at the downstream end of the table.
These automatic vibrating tables present these particular drawbacks:                noisy operation;        low productivity requiring a strict control of the output of equipment positioned upstream of the sorting table (feeding device, de-stalker, etc.);        a rather imperfect result, keeping in mind that any debris of a size smaller than the berries can pass through the perforations of the tray and are therefore not evacuated; and        cannot be placed on a grape-picking machine.        
In a different agricultural domain, olive or nut picking machines are known to include a sorting system consisting of a succession of identical, parallel rolls that are close to each other, and provided with grooves and helicoidal threading extending from one end of the rolls to the other. In this way, the number of openings are arranged between two adjacent helicoidal rolls, these openings being sized so allow the passage and drop-off of the small harvested fruit, whereas the foreign matter of sizes larger than the size of the fruit “float” on the rolls and are evacuated to one of the side edges of the sorting surface.
The drawbacks of these devices and their operation method are that they lead to the crushing of a more than negligible percentage of the fruit, that they let leaf stalks, twigs and other debris of an elongated shape pass through, and that they cause a skewed displacement of the treated products, thus leaving an unused area of screening and creating a disturbance in the operation. Nor do these devices allow the elimination of foreign matter of a size that is smaller than the dimensions of the openings made between the rolls, so that the cleaning of the crop remains very imperfect. To remedy this drawback, it is necessary to have a screening device consisting of an endless conveyor with fixed close bars that are separated by small size slots allowing the evacuation, by gravity, of small sized debris during the ascending travel of the crop towards the sorting system. Such an arrangement considerably lengthens the sorting device and excludes any possibility of mounting it on a harvesting machine such as a grape-picker.
Still in a different agricultural domain (sizing of potatoes), machines are known (German Patent No. 1965243) which include a number of profiled cylinders positioned parallel to each other in succession, these cylinders being constituted each by coaxial discs presenting conical ridges, so that each profiled cylinder delimits, together with the adjacent cylinders, a number of adjustable openings. The ends of the profiled cylinders are hooked on endless chains, the upper run of which is essentially horizontal, the rolls being driven in rotation by means of a rack during their upper horizontal travel. The profiled cylinders are thus driven in translation.
These machines are thus designed in the form of an endless calibrating conveyor belt with an upper calibrating side and a lower return side which has these particular drawbacks:                they are bulky because of the need to install a container for the recovery of the sized products between the upper calibrating side and the return side of the endless conveyor belt; and        they are complex and costly.        
In the prior art document, European Patent 0951950, there is also described a potato sizing machine operating on the same principle and having the additional drawback of being more complex and more expensive.
Furthermore, the sizing machines for products such as potatoes, described in documents DE 1965243 and EP 0951950 cannot be used for the elimination of small foreign matter mixed in with the grape berries, after the de-stalking of the bunches of grapes. It becomes clear, in fact, that nothing has been provided to prevent any small foreign matter from passing through the openings in the endless calibrator conveyor belt, together with the sized products.
It is the particular aim of the invention to remedy these drawbacks or at least to significantly improve the results obtained in the operation of the known machinery.